Largest known comet is heading close enough to us to become visible
Largest known comet is heading close enough to us to become visible By Ashley Strickland, CNN enablePagination: false endIndex: (CNN) — Astronomers have discovered the largest known comet, and it's about a thousand times more massive than others. Comet Bernardinelli-Bernstein, so named because it was found by University of Pennsylvania department of physics and astronomy graduate student Pedro Bernardinelli and Professor Gary Bernstein, is between 62 to 124 miles (100 to 200 kilometers) across. The team announced the discovery in June. This unusual comet will make its closest approach to o...